Solve for $x$ : $2\sqrt{x} + 7 = 9\sqrt{x} + 4$
Explanation: Subtract $2\sqrt{x}$ from both sides: $(2\sqrt{x} + 7) - 2\sqrt{x} = (9\sqrt{x} + 4) - 2\sqrt{x}$ $7 = 7\sqrt{x} + 4$ Subtract $4$ from both sides: $7 - 4 = (7\sqrt{x} + 4) - 4$ $3 = 7\sqrt{x}$ Divide both sides by $7$ $\frac{3}{7} = \frac{7\sqrt{x}}{7}$ Simplify. $\dfrac{3}{7} = \sqrt{x}$ Square both sides. $\dfrac{3}{7} \cdot \dfrac{3}{7} = \sqrt{x} \cdot \sqrt{x}$ $x = \dfrac{9}{49}$